Amanda Coetzee
2 minute read
30 Jan 2020
11:28 am

Annual brown-veined butterfly migration has SA in a flutter

Amanda Coetzee

The butterflies originate in the dry regions of the Karoo and the Kalahari, and are common in the central, northern and north-eastern parts of South Africa, ending their journey near Mozambique.

A Brown-Veined White Butterfly is seen during a stop to replenish itself with nectar during its migration towards Madagascar, 29 January 2010. These butterflies migrate in numbers annually, but often use different routes collecting other butterflies en route, this year the route has included the greater Johannesburg area with thousands of butterflies passing throughout the last few days. Their migration takes them from the Western coast areas of South Africa across the entire country and then a short trip over the ocean towards Madagascar. Picture: Neil McCartney

The migration of the brown-veined white butterfly (Belenois aurota) in South Africa takes place during midsummer every year, filling the sky with white clouds of butterflies, reports Alberton Record.

According to Johan van der Walt, who wrote a blog for Wildlife South Africa about the butterflies, the migration of these butterflies affects especially the central, northern and north-eastern parts of South Africa, and depending on climatic conditions like rain and drought, their numbers differ every year.

Following them are hundreds of insect-eating birds and dragonflies for which the slow-moving, low-flying butterflies are easy prey.

Known as South Africa’s most common butterfly and occurring in most areas, the brown-veined white butterfly is also called the pioneer, pioneer white or caper white.

Of the family Pieridae, with a wingspan of about 45 mm, they originate in the dry regions of the Karoo and the Kalahari where they gather in their millions every year in December or January and take to the sky to migrate in a north-easterly direction.

The butterflies, which lay their eggs on the Shepherd’s Tree (Boscia albitrunca), owe their population strength to the tree, which is the main food source of the caterpillars. The masses of white butterflies probably play an important role in the pollination of the tree, but there is much not known about this ubiquitous butterfly.

After crossing the Northern Cape, parts of the Free State and North West Province on their journey northeast, they fly across Gauteng, parts of Mpumalanga and parts of Limpopo Province.

As they fly in a north-easterly direction from the Karoo and the Kalahari, more and more join the flight. They also pause to lay eggs along the way.

Van der Walt says little research has been done about where exactly the butterflies fly to, but they have been noticed flying above the ocean near the Mozambique coast, where at the end of their journey, they most probably fall into the ocean.

Twitter has been abuzz, with many South Africans posting about the butterflies.

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